Anyone who pulls a knife to threaten another human being deserves everything they get coming to them - regardless of their social or mental condition.
Neeson's reaction to me was perfectly viable. All it take is on puncture wound and Liam might never make it home.
Of course, teachers hitting students is a big no no, but also teachers shouldn't have to fear going to work and should be allowed to protect themselves within reason.
I had never heard this Liam Neeson story before, thanks for sharing 😁.